Calibration system for array antenna receiving apparatus

ABSTRACT

A calibration system of an array antenna receiving apparatus is us d for cellular mobile c mmunication systems. In the array antenna receiving apparatus of the present calibration system, a calibration time determining unit ( 111 ) determines an adaptive calibration time based on detection voltages of the total reception power inputted to antenna radio receiving units ( 104 - 1  to  104 -N). Next, a calibration signal processing unit ( 112 ) detects phaselamplitude information of a calibration signal from multiplexing signals outputted from the antenna radio receiving units based on the longest calibration time among the calibration times. User signal processing units ( 108 - 1  to  108 -M) correct outputs from the antenna radio receiving units based on the phase/amplitude information. Therefore, the deterioration of the reception sensitivity of a user signal to a mobile machine can be prevented and the reduction of the number of users in the cellular system can further be prevented.

TECHNICAL FIELD

[0001] The present invention relates to a calibration system of an arrayantenna receiving apparatus. More particularly, the present inventionrelates to a calibration system for correcting the change in phase(delay) and amplitude information between antenna radio receiving unitsin an array antenna receiving apparatus for adaptive antenna control.

BACKGROUND ART

[0002] Conventional cellular mobile communication systems require thehigh speed and the high quality of signals and the increase insubscriber capacity. For example, a method for reducing reception gainagainst the interference from another user and the interference due todelay waves is examined by using an array antenna receiving apparatuscomprising a plurality of antenna devices having the high correlation.As a result, a reception directive pattern is formed so that thereception gain is increased in the incoming direction of a desiredsignal.

[0003] The array antenna receiving apparatus comprises the plurality ofantenna radio receiving units. In general, in the above-mentioned arrayantenna receiving apparatus, the amplitudes and phases in the antennaradio receiving units connected to the antenna devices are individuallyvaried every moment. The formatting of the reception directive patternrequires the correction of the variation of the amplitudes and phases.The above operation is called calibration.

[0004] For example, Japanese Unexamined Patent Publication (JP-A) No.11-46180 discloses a conventional calibration system of theabove-mentioned array antenna receiving apparatus. Japanese UnexaminedPatent Publication No. 11-46180 prepares a technology in which awell-known signal is inputted to antenna radio receiving units connectedto antenna devices and a result of demodulating a calibration signal isused. In this preparation, the change in phases (delays) and amplitudesof the antenna radio receiving units, as the demodulating results, whichare individually varied every moment, are corrected.

[0005]FIG. 1 is a block diagram showing a calibration system of aconventional array antenna receiving apparatus.

[0006] The array antenna receiving apparatus comprises an array antenna1001, multiplexing circuits 1003-1 to 1003-N corresponding to N antennadevices 1002-1 to 1002-N, antenna radio receiving units 1004-1 to 1004-Ncorresponding to the N antenna devices 1002-1 to 1002-N, user signalprocessing units 1005-1 to 1005-M corresponding to M users, acalibration signal transmitting unit 1010, and a calibration signalprocessing unit 1011.

[0007] The array antenna 1001 comprises N antenna devices 1002-1 to1002-N. The N antenna devices 1002-1 to 1002-N are closely arranged sothat reception signals from the antenna devices have a correlation, andreceive signal obtained by multiplexing a desired signal and a pluralityof interference signals.

[0008] One multiplexing circuit 1003-i in the N multiplexing circuitsmultiplexes a calibration signal as an output from the calibrationsignal transmitting unit 1010 and a reception signal as an output fromthe antenna device 1002-i. The multiplexing circuit 1003-i multiplexesan input signal at a radio band and outputs the multiplexing signal tothe antenna radio receiving unit 1004-i. A multiplexing method is notparticularly limited and a code multiplex is used as an example.

[0009] The antenna radio receiving unit 1004-i comprises devices such asa low-noise amplifier, a band limiting filter, a mixer, a localtransmitter, an AGC (Auto Gain Controller), an orthogonal detector, alow-pass filter, and an analog/digital converter (ADC). The antennaradio receiving unit 1004-i subjects the signal inputted from themultiplexing circuit 1003-i to amplification, frequency conversion fromthe radio band to a base band, orthogonal detection, analog/digitalconversion, and so on. The antenna radio receiving unit 1004-i furtheroutputs the processed signal to the user signal processing unit 1005-iand the calibration signal processing unit 1011. Normally, an AGCamplifier is used for keeping of a power level of the output signalconstant independently of the power level of the input signal everyantenna radio receiving unit.

[0010] The calibration signal processing unit 1011 receives signals fromthe antenna radio receiving units 1004-1 to 1004-N, extracts thecalibration signal from the signals, detects phase/amplitude informationof the antenna radio receiving units 1004-1 to 1004-N, and outputs thedetected information to the user signal processing units 1005-1 to1005-M. Herein, the calibration signal multiplexed to the input signalcan be extracted.

[0011] A user signal processing unit 1005-j corresponding to a user jinputs outputs from the antenna radio receiving units 1004-1 to 1004-Nand the phase/amplitude information of the antenna radio receiving units1004-1 to 1004-N as outputs from the calibration signal processing unit1011. The user signal processing unit 1005-j corrects the inputs fromthe antenna radio receiving units 1004-1 to 1004-N by using thephase/amplitude information of the antenna radio receiving units 1004-1to 1004-N as the outputs from the calibration signal transmitting unit1010, and increases the reception gain against the incoming direction ofthe signal to the target user j. On the other hand, the user signalprocessing unit 1005-j forms a reception directive pattern so that thereception gain is reduced against the interference from another user andthe interference due to the delay waves, and outputs a user demodulatingsignal j which is received by the reception directive pattern.

[0012] The calibration signal transmitting unit 1010 generates acalibration signal at the base band and subjects the generated signal todigital/analog conversion and frequency conversion from the base band tothe radio band. Thereafter, the calibration signal transmitting unit1010 forms the calibration signal having the same frequency band as thatof reception signals of the antenna devices 1002-1 to 1002-N, andoutputs the formed signal to the multiplexing circuits 1003-1 to 1003-Nat arbitrary power levels. In this case, the calibration signalprocessing unit 1011 detects the phase/amplitude information of theantenna radio receiving units 1004-1 to 1004-N every reception power bychanging the calibration signals to have a plurality of power levels.

[0013] The signals received by each of the N antenna devices 1002-1 to1002-N include a users desired signal component, an interference signalcomponent, and thermal noise. Further, the desired signal component andthe interference signal component include multi-path components,respectively. Generally, the signal components comes in differentdirections.

[0014] The conventional array antenna receiving apparatus shown in FIG.1 identifies the signal components in different incoming directions andforms the reception directive pattern by using the phase/amplitudeinformation of the signals received by the N antenna devices 1002-1 to1002-N.

[0015] In this case, the antenna radio receiving units 1004-1 to 1004-Ngenerate the change in phase/amplitude therein. Then, informationdifferent from the phase/amplitude information of the signals receivedby each of the original antenna devices 1002-1 to 1002-N is given to theuser signal processing units 1005-1 to 1005-M. Thus, the signalcomponents are not accurately identified and an ideal receptiondirective pattern is not formed.

[0016] The calibration signals having the same frequency band as thoseof the reception signals from the antenna devices 1002-1 to 1002-N aremultiplexed thereto. The calibration signal processing unit 1011 detectsthe phaselamplitude information of the calibration signals extractedfrom the outputs from the antenna radio receiving units 1004-1 to1004-N, thereby correcting the phase/amplitude information given to theuser signal processing units 1005-1 to 1005-M.

[0017] The multiplex of the calibration signals enables the calibrationupon operating the array antenna receiving apparatus. That is, thecalibration signal is multiplexed to the reception signal and only thecalibration signal component can be extracted. For example, codemultiplex is used.

[0018] A non-linear circuit included in the antenna radio receivingunits 1004-1 to 1004-N, in particular, the AGC has the change inphase/amplitude varied depending on the reception power level.Therefore, the calibration signal processing unit 1011 extracts thecalibration signals of the outputs from the antenna radio receivingunits 1004-1 to 1004-N and detects the phase/amplitude information whilechanging the power levels of the calibration signals outputted by apower level varying circuit of the calibration signal transmitting unit1010. Thus, the amount of correction applied to the phase/amplitudeinformation given to the user signal processing units 1005-1 to 1005-Mis determined every power level of the calibration signal.

[0019] The array antenna receiving apparatus having the above-mentionedcalibration means can correct the phase/amplitude information given tothe user signal processing units 1005-1 to 1005-M if the change inphase/amplitude is caused in the antenna radio receiving units 1004-1 to1004-N upon operating the array antenna receiving apparatus. Further,the calibration with high accuracy can be performed corresponding to thepower levels of the reception signals.

[0020] Consequently, the conventional array antenna receiving apparatusshown in FIG. 1 accurately identifies the signal components varieddepending on the incoming directions by using the phase/amplitudeinformation of the reception signals of the N antenna devices 1002-1 to1002-N, and forms the ideal reception directive pattern.

[0021] However, the calibration system of the conventional array antennareceiving apparatus is not suitable to the array antenna receivingapparatus upon operation because it has the following problems.

[0022] First, the reception sensitivity of the array antenna receivingapparatus excessively deteriorates in case that the calibration signalsare changed at a plurality of power levels upon operating the arrayantenna receiving apparatus. Further, the phase/amplitude information ofthe antenna radio receiving units is detected every reception power,thereby performing the calibration. Because the calibration signal isentirely the interference wave for the desired wave as a user signalinputted from the antenna from a mobile machine and, in particular, ifthe calibration signal with a high level is inputted, the interferencesignal component is increased. Secondarily, the calibration reduces thenumber of users of the system. Because the calibration signal becomesthe interference wave and the ratio of the user signal from the mobilemachine to the interference signal deteriorates, and a transmissionoutput of the mobile machine is increased to demodulate the signal tohave a desired signal quality in a base station apparatus.

[0023] Accordingly, the present invention is devised to solve theabove-mentioned problems and it is an object of the present invention toprovide the following calibration system. First, the sensitivitydeterioration due to the calibration signal is prevented in the arrayantenna receiving apparatus upon operation and, further, the calibrationwith high accuracy can be performed irrespective of a simple structure.Secondarily, there is almost no reduction of the number of users of thecellular system.

DISCLOSURE OF INVENTION

[0024] A calibration system of an array antenna receiving apparatusaccording to the present invention relates to a calibration system of anarray antenna receiving apparatus for inputting a multiplexing signalwhich is obtained by multiplexing a well-known calibration signal tosignals received from antenna devices forming an array antennacorresponding to the antenna devices, for detecting phase/amplitudeinformation of the calibration signal every antenna radio receiving unitconnected to each antenna device, based on the calibration signalextracted from the multiplexing signals, and for correcting a usersignal to a mobile machine which is received every antenna radioreceiving unit connected to each antenna device based on thephase/amplitude information. For extracting the calibration signal andassuring the ratio between the calibration signal to be need forcalibration and the interference signal, the

[0025] Calibration system of the array antenna apparatus ischaracterized by comprising radio control means for detecting adetection voltage of the total reception power of the inputtedmultiplexing signal, for gain controlling the received multiplexingsignal in accordance with the detection voltage, and for outputting thesignal controlled, and signal processing means for receiving thedetection voltage of the total reception power from the control means,for determining an adaptive calibration time every antenna device basedon the detection voltage, and for detecting the phase/amplitudeinformation of the calibration signal from the multiplexing signal basedon the longest calibration time among the calibration times.

[0026] Specifically, the calibration system of the array antennareceiving apparatus comprises a calibration radio transmitting unit fortransmitting a well-known calibration signal, an antenna radio receivingunit connected to corresponding antenna devices forming an arrayantenna, for inputting a signal multiplexing the calibration signal to asignal received from each antenna device, a calibration signalprocessing unit for detecting phase/amplitude information of thecalibration signal every antenna radio receiving unit based on thecalibration signal extracted from each of the antenna radio receivingunits, and a user signal processing unit for correcting a multiplexingsignal, which is received by each of the antenna radio receiving unitsbased on the phase/amplitude information every antenna detected by thecalibration signal processing unit.

[0027] The calibration system of the array antenna receiving apparatusfurther comprises a radio control unit arranged to each of the antennaradio receiving units, for outputting an AGC control signal forcontrolling gain in accordance with a detection voltage of the totalreception power inputted to the corresponding antenna radio receivingunit, and a calibration time determining unit for determining andoutputting an adaptive calibration time every antenna radio receivingunit based on the detection voltage of the total reception powerinputted to each of the antenna radio receiving units. Therefore, eachof the antenna radio receiving units detects the detection voltage ofthe total reception power of the inputted multiplexing signal, outputsthe detection voltage to the radio control unit, and outputs gain of thereceived multiplexing signal by gain in accordance with the AGC controlsignal received from the corresponding radio control unit. And thecalibration signal processing unit detects and outputs thephase/amplitude information of the calibration signal from themultiplexing signal outputted from each of the antenna radio receivingunits based on the longest calibration time among the calibration timesof the antenna radio receiving units outputted from the calibration timedetermining unit.

[0028] The calibration signal transmitted by the calibration radiotransmitting unit is sent by fixed power which is sufficiently lowerthan thermal noise power in the array antenna receiving apparatus. Themultiplexing signals outputted from the antenna radio receiving unitsare added by using the common mode by the longest calibration time andthe calibration signals included in the multiplexing signals areaveraged. Thus, the phase/amplitude information of the calibrationsignal is detected every antenna radio receiving unit. That is, thephaselamplitude information of the calibration signal by varying thecalibration period using the calibration signal having the fixed lowpower which does not cause the deterioration of the sensitivity.

[0029] With the above-mentioned structure, the sensitivity deteriorationdue to the calibration signal can be prevented. The reduction of thenumber of users in the cellular system can further be prevented.Moreover, the phase/amplitude information can accurately be correctedwith simple structure.

[0030] The calibration signal transmitted from the calibration radiotransmitting unit may be sent by the fixed power which is sufficientlylower than thermal noise power in the array antenna receiving apparatus.When the calibration signal processing unit detects the phase/amplitudeinformation, the multiplexing signals outputted from the antenna radioreceiving units are added by using the common mode by the longestcalibration time and the calibration signals included in themultiplexing signals are averaged. Thus, the phase/amplitude informationof the calibration signal may be detected every antenna radio receivingunit. Further, the phase/amplitude information of each antenna radioreceiving unit may be detected every calibration period having a periodlength of the longest calibration time.

[0031] The calibration time determining unit may determine and outputthe adaptive calibration time every antenna radio receiving unit basedon the AGC control signal from each of the radio control units, in placeof the detection voltage of the total reception power.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032]FIG. 1 is a block diagram of a calibration system of aconventional array antenna receiving apparatus;

[0033]FIG. 2 is a block diagram showing a calibration system of an arrayantenna receiving apparatus according to one embodiment of the presentinvention;

[0034]FIG. 3 is a diagram showing one format of characteristics for theamount of deterioration of the reception sensitivity of the calibrationsignal;

[0035]FIG. 4 is a diagram showing one format of the distribution of thetotal reception power before an AGC in each antenna receiving unit;

[0036]FIG. 5 is a diagram showing another format of the distribution ofthe total reception power after the AGC in each antenna receiving unit;

[0037]FIG. 6 is a diagram showing one format of the calibration signalafter inverse diffusion from each antenna receiving unit;

[0038]FIG. 7 is a diagram showing one format of correlativecharacteristics between processing gain and averaging time using thecommon-mode addition; and

[0039]FIG. 8 is a block diagram showing a calibration system of an arrayantenna receiving apparatus according to another embodiment of thepresent invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0040] A detailed description is made about the present invention withreference to the drawings.

[0041]FIG. 2 is a block diagram showing a calibration system of an arrayantenna receiving apparatus according to one embodiment of the presentinvention.

[0042] The array antenna receiving apparatus comprises N (N is aninteger not less than 2) antenna devices 102-1 to 102-N, multiplexingcircuits 103-1 to 103-N, antenna radio receiving units 104-1 to 104-Nthat include total reception power detecting units 105-1 to 105-N andAGC (Auto Gain Controller) 106-1 to 106-N respectively, user signalprocessing units 108-1 to 108-M corresponding to M users, a calibrationsignal transmitting unit 110, a calibration time determining unit 111,and a calibration signal processing unit 112.

[0043] The array antenna 101 comprises N antenna devices 102-1 to 102-Nthat are closely arranged with high antenna-correlation. One side of amultiplexing circuit 103-i corresponding to an antenna device 102-i inthe N antenna devices is connected to the antenna device 102-i and thecalibration signal transmitting unit 110 and inputs the outputstherefrom. The multiplexing circuit 103-i multiplexes the two inputsignals at a radio band and outputs the multiplexing signals to theantenna radio receiving unit 104-i connected to the other side of themultiplexing circuit 103-i.

[0044] The antenna radio receiving unit 104-i mainly comprises alow-noise amplifier, a band limiting filter, a mixer, a localtransmitter, a total reception power detecting unit 105-i, an AGC 106-i,an orthogonal detector, a low-pass filter, and an analog/digitalconverter. Herein, in the main components, only the total receptionpower detecting unit 105-i and the AGC 106-i as a feature of the presentinvention, different from the conventional ones, are shown anddescribed.

[0045] The total reception power detecting unit 105-i receives an outputfrom the multiplexing circuit 103-i and the inputted multiplexing signalis outputted to the AGC 106-i. A detection voltage of the multiplexingsignal is outputted to a radio control unit 107-i and the calibrationtime determining unit 111.

[0046] The AGC 106-i amplifies or attenuates the multiplexing signalinputted from the total reception power detecting unit 105-i inaccordance with an AGC control voltage inputted from the radio controlunit 107-i, and always outputs constant power to all the user signalprocessing units 108-1 to 108-M and the calibration signal processingunit 112.

[0047] The radio control unit 107-i that is added to the above-mentionedconventional structure outputs the AGC control voltage to the AGC 106-iin accordance with the detection voltage inputted from the totalreception power detecting unit 105-i.

[0048] A user signal processing unit 108-j corresponding to a user j asone of the M users inputs outputs from the antenna radio receiving units104-1 to 104-N and the phase/amplitude information corresponding to theantenna radio receiving units 104-1 to 104-N as outputs from thecalibration signal processing unit 112. The user signal processing unit108-j corrects the outputs from the antenna radio receiving units 104-1to 104-N by using the phaselamplitude information of the antenna radioreceiving units 104-1 to 104-N and increases the reception gain againstthe incoming direction of the user signal corresponding to the user j.On the other hand, the user signal processing unit 108-j forms thereception directive pattern so that the reception gain is reducedagainst the interference from another user and the interference due tothe delay wave. The user signal processing unit 108-j outputs a userdemodulating signal j of the user j, which is r ceiv d by the formedreception directive pattern.

[0049] The calibration signal transmitting unit 110 generates thecalibration signal at a base band and generates an arbitrary symbolpattern as the calibration signal. The calibration signal transmittingunit 110 subjects the generated calibration signal at the base band todigital/analog conversion, frequency conversion from the base band tothe radio band, and the like, and outputs the calibration signal havingwell-known fixed power to all the multiplexing circuits 103-1 to 103-N.

[0050] The calibration time determining unit 111 which is added to theabove-mentioned conventional structure obtains an adaptive calibrationtime for each of the antenna radio receiving units 104-1 to 104-N basedon the detection voltages inputted from the total reception powerdetecting units 105-1 to 105-N, and outputs the obtained calibrationtime to the calibration signal processing unit 112.

[0051] Unlike the conventional calibration signal processing unit, thecalibration signal processing unit 112 receives the adaptive calibrationtime for each of the antenna radio receiving units 104-1 to 104-N fromthe calibration time determining unit 111.

[0052] The calibration signal processing unit 112 inputs outputs fromthe antenna radio receiving units 104-1 to 104-N and the calibrationtime received from the calibration time determining unit 111, extractsthe multiplexed calibration time to the outputs from the antenna radioreceiving units 104-1 to 104-N, detects the phase/amplitude informationof the antenna radio receiving units 104-1 to 104-N, and outputs theinformation of all the antenna radio receiving units 104-1 to 104-N toall the user signal processing units 108-1 to 108-M. The calibrationsignal is a coding multiplexing signal and then the calibration signalis extracted by inverse diffusion.

[0053] Next, the operation will be described with reference to FIG. 2.

[0054] An array antenna 101 comprises N antenna devices 102-1 to 102-N.The N antenna devices 102-1 to 102-N are closely arranged so thatreception signals of the antenna devices have a high correlation, andreceive signals obtained by multiplexing a desired signal and aplurality of interference signals. However, actually, the increase inantenna devices reduces the correlation between the antenna deviceswhich are not adjacent and far from each other and causes largevariation in power of the received multiplexing signals. That is, theantenna devices of the array antenna receiving apparatus receivedifferent power.

[0055] On the other hand, the calibration signal at the base band whichis generated by the calibration signal transmitting unit 110 isfrequency-converted and amplified, and is sent as well-known and fixedpower.

[0056] Each of the multiplexing circuits 103-1 to 103-N is connected tothe antenna devices 102-1 to 102-N and one calibration signaltransmitting unit 110 at one side thereof, and inputs the calibrationsignal outputted from the calibration signal transmitting unit 110 andthe outputted signal from the antenna devices 102-1 to 102-N. Each ofthe multiplexing circuits 103-1 to 103-N multiplexes the two inputs atthe radio band and outputs the multiplexed signals to the antenna radioreceiving units 104-1 to 104-N connected to the other side thereof.

[0057] For example, when the reception sensitivity of the calibrationsignal of a desired signal as a user signal from a mobile machinedeteriorates to 0.2 dB or less, equivalently, the noise power leveldeteriorates to 0.2 dB. Therefore, it is assumed that the thermal noisepower level is 0 dB, the following formula may be calculated.

0.2>10×log(10^(0/10)+10^(X/10))

[0058] Thus, a relation of “x<−13.267 dB” is obtained. Accordingly,transmission power of the calibration signal is to be fixed to a levellower than the thermal noise power level, that is, a level lower than“−13.267 dB”.

[0059]FIG. 3 shows the amount of deterioration of the receptionsensitivity of the calibration signal.

[0060] Herein, output signals from the multiplexing circuits 103-1 to103-N are the calibration signal, desired signal, interference signal,and thermal noise. When it is assumed that the total of the outputsignals are the total reception power, the calibration signal and thethermal noise have constant power and, therefore, the differences of thetotal power outputted from the multiplexing circuits become thedifferences of power obtained by adding the desired signal and theinterference signal which are inputted from the antenna devices.

[0061] Consider the two antenna radio receiving units 104-1 and 104-Nhereinbelow. The total reception power detecting unit 105-1 receives theoutput from the multiplexing circuit 103-1 and the inputted multiplexingsignal is outputted to the AGC 106-1. The total reception powerdetecting unit 105-N receives the output from the multiplexing circuit103-N and the inputted multiplexing signal is outputted to the AGC106-N. However, the total reception power detecting units 105-1 and105-N output detection voltages of the signals multiplexed to the radiocontrol units 107-1 and 107-N respectively and the calibration timedetermining unit 111. For example, it is assumed that the detectionvoltage of the total reception power detecting unit 105-1 of the totalreception power inputted to the antenna radio receiving unit 104-1 is2.5V and the detection voltage of the total reception power detectingunit 105-N of the total reception power inputted to the antenna radioreceiving unit 104-N is 2.8V. The difference 0.3V of the detectionvoltages becomes the difference between “addition of the desired signaland the interference signal” among all the power inputted to the antennaradio receiving unit 104-1 and “addition of the desired signal and theinterference signal” among all the power inputted to the antenna radioreceiving unit 104-N.

[0062] Consequently, the “addition of the desired signal and theinterference signal” as the interference signal for the calibrationsignal is inputted to the antenna radio receiving unit 104-N by thedetection voltage of 0.3V. This means that a C/N ratio of thecalibration signal is not constant. This state is shown in FIGS. 4 to 7.

[0063]FIG. 4 is a diagram showing the power distribution of the antennaradio receiving units before gain control by the AGC. FIG. 5 is adiagram showing the power distribution of the receiving units after thegain control by the AGC. FIG. 6 is a diagram showing the C/N ratio ofthe calibration signals which are averaged by using the common-modeaddition by the same time by the calibration signal processing unit 112.

[0064] The detection voltages outputted by the total reception powerdetecting units 105-1 and 105-N are inputted to the radio control units107-1 and 107-N respectively and the AGC control voltage is outputted sothat output power of the AGC 106-1 to AGC 106-N is constant. The AGCs106-1 and 106-N control gain in accordance with the control voltageoutputted from the radio control units 107-1 and 107-N corresponding tothe AGCs. Further, the AGCs 106-1 and 106-N output the multiplexingsignal which is amplified or attenuated to all the user signalprocessing units 108-1 to 108-M corresponding to the users 1 to M and tothe calibration signal processing unit 112. In this case, the AGCs 1061and 106N similarly control the gain of the calibration signal and theinterference signal and therefore the C/N ratio of the calibrationsignal is not changed.

[0065] The detection voltages detected by the total reception powerdetecting units 105-1 and 105-N are simultaneously outputted to thecalibration time determining unit 111. Therefore, the calibration timedetermining unit 111 outputs the calibration times corresponding to thedetection voltages to the calibration signal processing unit 112.Herein, it is defined that the calibration time is the total time of aprocessing time for correction and an averaging time obtained byinversely diffusing the calibration signals and by using the common-modeaddition in the calibration signal processing unit 112. Further, it isassumed that the processing time is constant. Information outputted tothe calibration signal processing unit 112 from the calibration timedetermining unit 111 is calibration time and the number of the antennaradio receiving unit. As described above, since the calibration signaland the noise power are always constant, the calibration timedetermining unit 111 uniquely determines the calibration times of theantenna radio receiving units 104-1 and 104-N only by the detectionvoltages from the total reception power detecting units 105-1 and 105-N.

[0066] The calibration signal processing unit 112 receives the outputsfrom the antenna radio receiving units 104-1 and 104-N. The calibrationsignal processing unit 112 extracts the calibration signal multiplexedto the outputs of the antenna radio receiving units 104-1 and 104-N,detects the phase/amplitude information of the antenna devices 102-1 and102-N, and outputs the detected information to the corresponding usersignal processing units 108-1 and 108-M. In this case, the calibrationsignal processing unit 112 selects the longest calibration time amongthe calibration times outputted from the calibration time determiningunit 111, and performs the averaging processing by adding thecalibration signals by the common mode in accordance with the selectedcalibration times.

[0067] The processing gain of the calibration signal depends only on thetime for averaging the demodulated calibration signals by using thecommon-mode addition. Therefore, in order to obtain a predetermined C/Nratio required for comparing the phase and amplitude information, theaveraging processing time obtained by using the common-mode addition maybe added to the antenna radio receiving unit having the largestinterference signal components for the calibration signal. FIG. 7 showsthe processing gain for the averaging processing time using thecommon-mode addition. Referring to FIG. 7, since the ratio of thecalibration signal to the interference signal is varied depending on theantenna radio receiving units, as will be understood, the C/N ratioafter the inverse diffusion necessary to compare the phase/amplitudeinformation with high accuracy requires the averaging processing timeusing the common-mode addition varied depending on the antenna radioreceiving units.

[0068] With regard to a calibration period, it is assumed that thecalibration period corresponds to the longest calibration time among thecalibration times of the antenna radio receiving units which areoutputted from the calibration time determining unit 111. That is, whenthe power of the interference signal for the calibration signal is low,the calibration period may be short. On the other hand, when the powerof the interference signal for the calibration signal is high, a longcalibration period is required. Therefore, when the previous calibrationoperation ends, the next calibration operation starts and thecalibration period for the next calibration is determined by the outputresult of the calibration time determining unit 111. When the detectionvoltage of the total reception power detecting unit 105-1 of the totalreception power inputted to the above-mentioned antenna radio receivingunit 104-1 is 2.5V and the detection voltage of the total receptionpower detecting unit 105-N of the total reception power inputted to theantenna radio receiving unit 104-N is 2.8V, the calibration timenecessary for the antenna radio receiving unit 104-N having the highdetection voltage becomes the calibration time for the presentcalibration.

[0069] The user signal processing units 108-1 to 108-M corresponding tothe user-1 to user-M respectively receive the outputs from the antennaradio receiving units 104-1 and 104-N and the phase/amplitudeinformation of the antenna devices 102-1 and 102-N as the outputs of thecalibration signal processing unit 112. For example, the user signalprocessing unit 108-j corresponding to the user-j corrects the outputsfrom the antenna radio receiving units 104-1 and 104-N by using thephase/amplitude information of the antenna devices 102-1 and 102-N andsimultaneously forms the reception directive pattern so that thereception gain is increased against the user signal incoming directionof the user-j and the reception gain is reduced against the interferencefrom another user and the interference due to the delay wave. Further,the user signal processing unit 108-j outputs a user demodulatingsignal-j which is received by the reception directive pattern.

[0070] As mentioned above, the calibration time necessary for detectingthe phase/amplitude information of the calibration signal is informedfrom the calibration time determining unit by using the calibrationsignal of the fixed power having the well-known level, therebyperforming the calibration without deteriorating the receptionsensitivity upon operating the system.

[0071] Next, an array antenna receiving apparatus will be described withreference to FIG. 8 according to another embodiment. FIG. 8 is a blockdiagram showing an array antenna receiving apparatus different from thatin FIG. 2 and components are the same as those described with referenceto FIG. 2 and are designated by the same reference numerals.

[0072] Referring to FIG. 8, an input of the calibration time determiningunit 111 is unlike that in FIG. 2. Referring back to FIG. 2, thedetection voltages outputted from the total reception power detectingunits 105-1 to 105-N in the antenna radio receiving units are inputted.However, referring to FIG. 8, the AGC control signals outputted to theAGCs 106-1 to 106-N by the radio control units 107-1 to 107-N areinputted and the calibration times necessary for the antenna radioreceiving units are outputted to the calibration signal processing unit112. With any structure, the same operations and advantages areobtained.

[0073] As mentioned above, in the calibration system of the presentinvention, first, the calibration time determining unit determines theadaptive calibration time every antenna radio receiving unit based onthe detection voltage of the total reception power inputted to theantenna radio receiving unit. Next, in the calibration system, thecalibration signal processing unit detects and outputs thephase/amplitude information of the calibration signal from themultiplexing signal outputted from the antenna radio receiving unitbased on the longest calibration time among the determined calibrationtimes. Therefore, in the calibration system of the present invention,the sensitivity caused by the calibration signal does not deteriorate.

[0074] Secondarily, in the calibration system, in order to obtain theC/N ratio necessary for comparing the phase/amplitude information ofthe, calibration signals, the averaging processing time using thecommon-mode addition of the calibration signals is controlled.Therefore, it is prevented that the calibration signal becomes theinterference signal and this deteriorates the ratio of the user signalfrom the mobile machine to the interference signal, and it is furtherprevented that the transmission output of the mobile machine fordemodulating the signal to have the desired signal quality in the basestation apparatus is increased. As a result, in the calibration system,the number of users in the cellular system is not reduced.

[0075] Thirdly, in the calibration system, only the time for adding thecalibration signals by the common mode and averaging the time iscontrolled for the total reception power received by the antennareceiving unit. Thus, the desired C/N ratio of the calibration signalafter the inverse diffusion can always be satisfied. Accordingly, in thecalibration system, the phase/amplitude information can accurately becorrected with simple structure.

INDUSTRIAL APPLICABILITY

[0076] As mentioned above, the calibration system of the array antennareceiving apparatus according to the present invention is suitable to acalibration system for correcting the change in phase (delay) andamplitude information between antenna radio receiving units in an arrayantenna receiving apparatus for adaptive antenna control such as acellular mobile communication system.

1. A calibration system of an array antenna receiving apparatus, forinputting a multiplexing signal which is obtained by multiplexing awell-known calibration signal to signals received from antenna devicesforming an array antenna corresponding to the antenna devices, fordetecting phase/amplitude information of the calibration signal everyantenna radio receiving unit connected to each antenna device, based onthe calibration signal extracted from the multiplexing signals, and forcorrecting a user signal to a mobile machine which is received everyantenna radio receiving unit connected to each antenna device based onthe phase/amplitude information, said calibration system comprising:radio control means for detecting a detection voltage of the totalreception power of the inputted multiplexing signal and for gaincontrolling the received multiplexing signal in accordance with thedetection voltage and for outputting the controlled signal as a signalfor extracting the calibration signal; and signal processing means forreceiving the detection voltage of the total reception power from saidcontrol means, for determining an adaptive calibration time everyantenna device based on the detection voltage, and for detecting andoutputting the phase/amplitude information of the calibration signalfrom the multiplexing signal based on the longest calibration time amongthe calibration times.
 2. A calibration system of an array antennareceiving apparatus comprising a calibration radio transmitting unit fortransmitting a well-known calibration signal, an antenna radio receivingunit connected to corresponding antenna devices forming an arrayantenna, for inputting a signal multiplexing the calibration signal to asignal received from each antenna device, a calibration signalprocessing unit for detecting phase/amplitude information of thecalibration signal every antenna radio receiving unit based on thecalibration signal extracted from each of said antenna radio receivingunits, and a user signal processing unit for correcting a user signal toa mobile machine, which is received by each of said antenna radioreceiving units based on the phase/amplitude information every antennadetected by said calibration signal processing unit, said calibrationsystem further comprising: a radio control unit arranged to each of saidantenna radio receiving units, for outputting an AGC control signal forcontrolling gain in accordance with a detection voltage of the totalreception power inputted to the corresponding antenna radio receivingunit; and a calibration time determining unit for determining andoutputting an adaptive calibration time every antenna radio receivingunit based on the detection voltage of the total reception powerinputted to each of said antenna radio receiving units, wherein each ofsaid antenna radio receiving unit detects the detection voltage of thetotal reception power of the inputted multiplexing signal, outputs thedetection voltage to said radio control unit, and outputs gain of thereceived multiplexing signal by gain in accordance with the AGC controlsignal received from the corresponding radio control unit, and saidcalibration signal processing unit detects and outputs thephase/amplitude information of the calibration signal from themultiplexing signal outputted from each of said antenna radio receivingunits based on the longest calibration time among the calibration timesof the antenna radio receiving units outputted from said calibrationtime determining unit.
 3. A calibration system of an array antennareceiving apparatus according to claim 2, wherein said calibration radiotransmitting unit transmits the calibration signal which is multiplexedand inputted to each of said antenna radio receiving units by fixedpower which is sufficiently lower than thermal noise power in said arrayantenna receiving apparatus.
 4. A calibration system of an array antennareceiving apparatus according to claim 2, wherein said calibrationsignal processing unit adds the multiplexing signals outputted from saidantenna radio receiving units by using the common mode by the longestcalibration time and averages the calibration signals included in themultiplexing signals, thereby detecting the phase/amplitude informationof the calibration signal every antenna radio receiving unit.
 5. Acalibration system of an array antenna receiving apparatus according toclaim 2, wherein said calibration signal processing unit detects andoutputs the phase/amplitude information of each antenna radio receivingunit every calibration period having a period length of the longestcalibration time.
 6. A calibration system of an array antenna receivingapparatus according to claim 2, wherein said calibration timedetermining unit determines and outputs the adaptive calibration timeevery antenna radio receiving unit based on the AGC control signal fromeach of said radio control units, in place of the detection voltage ofthe total reception power.